- Email: [email protected]
Contact in gear lubrication. (in French)
LITERATURE
ANI,
CURRENT
EVENTS
325 4.2.
4. I. General
Viscous Flow between Rotating Concentric Cylinders with a Circumferential Pressure Gradient at Speeds above Critical. K. C. Diprima, ASLE Tmns., 7 (1964) 333-341. For sufficiently high speeds of the inner cylinder, the flow between concentric rotating cylinders with a circumferential pressure gradient is unstable. By considering the full nonlinear equations, the amplitude of the resulting vortex motion is computed. The effect of the vortex motion on the shear stress at the inner cylinder and the relation between the mean flow and the pressure gradient are discussed.
The Effect of Lubricant Viscosity on Rear Axle Gear and Pinion Bearing Operation. K. McClintock and R. E. Osborne, Lubrication Eng., 20 (IO) (1964) 387-392; 6 figs., 5 tables, 3 refs. The effect of lubricant viscosity on rear axle gear and pinion tapered roller bearing operation at high temperatures (about 180-270°F) has been evaluated in both car and bench tests. Additive-treated lubricants having viscosities as low as 4.3 centistokes at 210°F provide satisfactory gear scoring protection. Satisfactory pinion bearing scoring protection is provided by additive-treated lubricants having viscosities as low as 2.5 centistokes at 2 10°F. Pinion bearing break-in wear is little affected by lubricant viscosity; however, wear over an extended period increases when viscosity is decreased. Optimum bcaring efficiency is observed with a lubricant having a viscosity at 210°F of about 4 centistokes.
Contact in Gear Lubrication. (In French) M. Godet, Compt. Rend. Acad. Sci. Paris, 258 (‘964) 4431-4433: 2 refs. Gear lubrication studies are made easier if one introduces the notion of contact and if one considers the “active” and “resultant” conditions which exist at the contact point. Taper-slot Machines. (In German) W. Rodenacker, Chem.-Ing.-Tech., 36 (1964) 898-906; II figs., 5 tables, 13 refs. Taper-slot machines are especially suitable for the conveying and evacuation of nonNewtonian substances. Considerable quantities of material can be dealt with by using such machines, so that the latter can be considered for use in plastics processing. In these, volatile components can be removed from highly viscous liquids, usually by the apphcation of a vacuum, and other materials can be simultaneously worked in. The theory z~nderlytng the journal bearing can be employed in compv,ting_for these wachines:
Bearirzgs
The Effects of Speed, Load, and Film Thickness on the Performance of Gaslubricated, Tilting-pad Journal Bearings. E. J. Gunter, Jr., J. G. Hinkle and D. D. Fuller, ASLE Trans., 7 (1964) 353-365; 14 figs., 3 tables, 4 refs. This paper deals with the effects of lubricant compressibility on the pressure profile and total load capacity in a partial journal bearing; pivot pressure as a measure of shoe load capacity; shoe friction characteristics; and optimum shoe clearance ratios for various speeds. The parameteril is used as an indicator of the compressibility effect of gas in the bearing clearance. Spring and Damping Coefficients for the Tilting-pad Journal Bearing. J. W. Lund, ASLE Trans., 7 (1964) 342-352; 20 figs., 8 refs. A method for calculating spring and damping coefficients for the tilting-pad journal bearing is presented. The analysis includes the effect of pad inertia. Numerical results are given in form of design curves for the centrally pivoted 4-shoe, g-shoe, h-shoe, and Is-shoe journal bearing. A comparison with test results is included.
Further Comments on the Pressure Depression Effect in Externally Pressurized Gaslubricated Bearings. A. F. Stahler, ASLE Trans., 7 (1964) 366376; ‘7 figs., I table, 21 refs. The work of several authors on the pressure depression effect in externally pressurized gas-lubricated bearings is presented, and improved mathematical formulas and experimental evidence are introduced. The use of the free surface, water table analogue as an aid in the visualization and study of the pressure-depression effect is presented. Good qualitative agreement was found between this analogue and the available experimental data.
Effect of Journal Finish on Load Capacity and Reliability of Traction Motor Support Bearings. R. W. Avery, Lubrication Eng., 20 (11) (1964) 422-428; 9 figs., 8 refs. The load capacity and reliability of large sleeve bearings, such as traction motor support bearings, can be improved by maintaining the journal surface finish within prescribed limits, thus making possible hydrodynamic operation. The proper journal surface is one where the shaft has small roughness peaks and burnishes the bearing to a smooth surface so that very thin oil films will suffice to separate the journal and bearing. With a given oil viscosity, the thinner the oil film becomes, the greater is Wear,
8
(‘965)
320-331
ANI,
CURRENT
EVENTS
325 4.2.
4. I. General
Viscous Flow between Rotating Concentric Cylinders with a Circumferential Pressure Gradient at Speeds above Critical. K. C. Diprima, ASLE Tmns., 7 (1964) 333-341. For sufficiently high speeds of the inner cylinder, the flow between concentric rotating cylinders with a circumferential pressure gradient is unstable. By considering the full nonlinear equations, the amplitude of the resulting vortex motion is computed. The effect of the vortex motion on the shear stress at the inner cylinder and the relation between the mean flow and the pressure gradient are discussed.
The Effect of Lubricant Viscosity on Rear Axle Gear and Pinion Bearing Operation. K. McClintock and R. E. Osborne, Lubrication Eng., 20 (IO) (1964) 387-392; 6 figs., 5 tables, 3 refs. The effect of lubricant viscosity on rear axle gear and pinion tapered roller bearing operation at high temperatures (about 180-270°F) has been evaluated in both car and bench tests. Additive-treated lubricants having viscosities as low as 4.3 centistokes at 210°F provide satisfactory gear scoring protection. Satisfactory pinion bearing scoring protection is provided by additive-treated lubricants having viscosities as low as 2.5 centistokes at 2 10°F. Pinion bearing break-in wear is little affected by lubricant viscosity; however, wear over an extended period increases when viscosity is decreased. Optimum bcaring efficiency is observed with a lubricant having a viscosity at 210°F of about 4 centistokes.
Contact in Gear Lubrication. (In French) M. Godet, Compt. Rend. Acad. Sci. Paris, 258 (‘964) 4431-4433: 2 refs. Gear lubrication studies are made easier if one introduces the notion of contact and if one considers the “active” and “resultant” conditions which exist at the contact point. Taper-slot Machines. (In German) W. Rodenacker, Chem.-Ing.-Tech., 36 (1964) 898-906; II figs., 5 tables, 13 refs. Taper-slot machines are especially suitable for the conveying and evacuation of nonNewtonian substances. Considerable quantities of material can be dealt with by using such machines, so that the latter can be considered for use in plastics processing. In these, volatile components can be removed from highly viscous liquids, usually by the apphcation of a vacuum, and other materials can be simultaneously worked in. The theory z~nderlytng the journal bearing can be employed in compv,ting_for these wachines:
Bearirzgs
The Effects of Speed, Load, and Film Thickness on the Performance of Gaslubricated, Tilting-pad Journal Bearings. E. J. Gunter, Jr., J. G. Hinkle and D. D. Fuller, ASLE Trans., 7 (1964) 353-365; 14 figs., 3 tables, 4 refs. This paper deals with the effects of lubricant compressibility on the pressure profile and total load capacity in a partial journal bearing; pivot pressure as a measure of shoe load capacity; shoe friction characteristics; and optimum shoe clearance ratios for various speeds. The parameteril is used as an indicator of the compressibility effect of gas in the bearing clearance. Spring and Damping Coefficients for the Tilting-pad Journal Bearing. J. W. Lund, ASLE Trans., 7 (1964) 342-352; 20 figs., 8 refs. A method for calculating spring and damping coefficients for the tilting-pad journal bearing is presented. The analysis includes the effect of pad inertia. Numerical results are given in form of design curves for the centrally pivoted 4-shoe, g-shoe, h-shoe, and Is-shoe journal bearing. A comparison with test results is included.
Further Comments on the Pressure Depression Effect in Externally Pressurized Gaslubricated Bearings. A. F. Stahler, ASLE Trans., 7 (1964) 366376; ‘7 figs., I table, 21 refs. The work of several authors on the pressure depression effect in externally pressurized gas-lubricated bearings is presented, and improved mathematical formulas and experimental evidence are introduced. The use of the free surface, water table analogue as an aid in the visualization and study of the pressure-depression effect is presented. Good qualitative agreement was found between this analogue and the available experimental data.
Effect of Journal Finish on Load Capacity and Reliability of Traction Motor Support Bearings. R. W. Avery, Lubrication Eng., 20 (11) (1964) 422-428; 9 figs., 8 refs. The load capacity and reliability of large sleeve bearings, such as traction motor support bearings, can be improved by maintaining the journal surface finish within prescribed limits, thus making possible hydrodynamic operation. The proper journal surface is one where the shaft has small roughness peaks and burnishes the bearing to a smooth surface so that very thin oil films will suffice to separate the journal and bearing. With a given oil viscosity, the thinner the oil film becomes, the greater is Wear,
8
(‘965)
320-331